I was complaining about hiss with 8030C even at 1m50. Recently I swapped RCA to XLR cables for XLR to XLR, and hiss decreased. It is now less audible from that distance. Source is a CD player connected to a Little Beat MC2 pre-amp. I don't know why it is better now. Perhaps the RCA cable was picking some interferences?
In my experience RCA cable is trash. Even double/triple shielded stuff seems to add a little hiss. Now that I have a full digital 2.1 system, there is zero added hiss. Plugging in and unplugging the analog XLR cables for the surround speakers is the same. No additional hiss. Love it. Maybe it's just RCA equipment doesn't get made to high standards? Also, with all the stuff going through the airwaves these days, I wouldn't be surprised if the unshielded RCA connectors act as tiny antennae.